New Energy Option for 21st Century

Recent Progress in Solar Photovoltaic
Energy Conversion
Yoshihiro Hamakawa

Abstract

Thirdly, a new strategy for the renewable energy promotion, the so called -Fundamental
Principle to promote New Energy Development
and Utilization-, and its action plan for PV
technology development up to year of 2010
are introduced.
In the final part of the paper, the prospect of future industrialization of photovoltaics is discussed, then possible new roles tocontribute to global environmental issues by
the PV system developments are introduced.

A review is given on some important rolesof the solar PV technology in sustainable development of 21st century civilization. Firstly,
the motivations of the industrial developments
attributable to the energy revolutions sinceJames Watt’s steam engine of the 18th century are discussed. The transitions of natural
resources from solid (coal), liquid (oil) and gas(LNG, LPG) are closely related to not only the
economy of mass production, storage andtransportation but also environmental issues.
Secondly, a brief discussion is given on “the3E Trilemma “ which is the most important
issue facing in the 21st century’s civilization life.

Keywords: PV System, 3E-trilemma, environmental issue, clean energy
revolution, new sunshine
project, renewable energy

CHANGE IN THE CIVILIZATION LIFE WITH ENERGY RESOURCE
8
Solid (coal)Liquid (oil)Gas (LNG)

Electricity

7

Present

Energy Expenditure andTheir Prospect (GTOE/Y)

Driving Force of the Flow

6
5
4

B-747
(1973)• Mass Produce ability• Mass Transport & Distribution• Mass Consumption! Environmental Load
! CostPV Effect
A.E. Becquerel(1839)

3
James Watt
(PAT1765)

2

Wibur & Orville Wright(1903)Space Solar cell
W.R. Cherry(1965)

4
OIL

Thomas Edison(1877)

6
5

IT

3
2

Etienne Lenoir(1860)

Population

Nuclear Renewable
Power
Energy

LNG

1

1
Coal

0
1750

0
1800

1850

1900

1950

2000

2050

CALENDAR YEAR
Fig. 1 Evolutions of industrial developments in civilization life with the form of energy resources

Department of Photonics, Faculty of Science and Engineering, Ritsumeikan University
1-1-1 Nojihigashi, Kusatsu, Shiga ,525-8577 Japan
Tel: +81-77-561-3938 Fax: +81-77-561-3938 e-mail:hamakawa@se.ritsumei.ac.jp30

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2100

World Population (Billion)

7

8
Transition ofEnergy Form

1. Evolution of Civilization Life
with Energy Revolutions
The industrial revolution started with theinvention of steam engine by James Watt in
1765. However, technological maturity fromR & D to market penetration, usually takes 1530 years. The steam ship and the steam locomotive fueled by coal were developed in the
19th century. The same is true during the petroleum age, that is, Etienne Lenoir’s invention of the internal combustion engine was in1860 [1], but the petroleum age bloomed in20th century with the development of gasoline engines for the automobile and the airplane. Figure 1 shows the changes in civilization with form of the energy resource since
the start of the industrial revolution. Energy
expenditures for the three main fossil fuels areplotted separately up to the year of 2000, andtheir future prospects are also predicted (thedashed lines in the figure) by following therenewable energy promotion scenario. From
the observation of the relation between theindustrial developments and their origins ofenergy resources, coal → oil → gases including LNG and recent LPG, the key issues are
the convenience to respond to mass consumption of energy, that is, mass production technology, and ease of transport and storage. The
driving force in the energy revolution is based
upon the so called “the Great Principle ofEconomy”.
With this economy of usage reason, theform of primary energy resources have evolved
from solid, liquid to gases. Another reasonsoriginate from the environmental load. As canbe seen from Table 1[2], the pollutant emission
factor for electricity generation per kWh.on
the unit of carbon equivalent gram is 322.8
for coal, 258.5 for oil and 178.0 for LNG, respectively. According to the recent energy
analysis survey [3], the electricity generation
factor in secondary energy is more than 40%
in developed countries, and will increase to

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50% in the 21 st century.
Electricity is the most convenient energy form, forthe above-mentioned reasons, with respect to mass
production, transport anddistribution.

Table 1 Pollutant Emission Factors for Electrical Generation (g/k Wh)

Pollutant Emission Factors For Electrical
Generation (g/kWh): The Total Fuel Cycle
Energy Source

CO2

NOx

SOx

Coal

322.8

1.8

3.400

Oil

258.5

0.88

1.700

Natural Gas

178.0

0.9

0.001

7.8

0.003

0.030

NuclearPhotovoltaics

5.3

0.007

0.020

Biomass

0.01

0.6

0.140

Geothermal

51.5

TR

TR

Wind

6.7

TR

TR

Solar Thermal

3.3

TR

TR

Hydropower

5.9

TR

TR

2 . 3 E - Tr i l e m m a
and New Energy
Strategy
In the discussions of theGrand Design for the 21st
century’s civilization, great
attention is focused on the
3E-Trilemma. That is, forthe activation of economic
development (E:Economy)
to occur, we need to increase energy expenditure(E:Energy). However, thisraises the environmental issue (E:Environment) of
more emissions of pollutant
gases. On the other hand,the political option to restrain pollutant gas emission halts economic development. This problem iscalled the 3E-Trilenma.
Figure 2 shows an illustra-

Ac
tiv
a

se
rea
c
n
I
te

Increase

Energy

my
ono
Ec

Pol
lut
io
n

Decrease

Activation

Energy
an
Cle
of

n

Deve
lop
me
nt

ion
miss
sE
Ga

Pop
ula
tio

TR=trace*Fossil fuel emission factors provided hy The American Gas Association; for nuclear
and renewable energy sources from the Council for Renewable Energy Education.
|with biomass fuel regrowth program

Destruction

CLEAN ENERGY

EconomyEnvironment

Slowdown

PreservationRec e s sio n E c o n o m ic A cti v ity

Fig. 2 3E-Trilemma, the most important task assigned to 21st century’s civilization. Only way to solve it is todevelop clean energy technology.

tion of the cyclic correlation of economy, energy and environment [4]. Here, importance isplaced on the change in the circuit from theinfrastructure of fossil fuel’s energy supply tothat of renewable energy development andsupply. According to the result of world energy trends analysis, the energy consumption
per capita in a country is directly proportional
to the country’s annual income per capita or
its GNP (Gross National Product) [4]. On theother hand, the world’s population is steadily
increasing as shown in Figure 3 (it reachedabout 6.1 billion in the year 2000), and it canbe expected that worldwide energy demand
will increase by multiples of the population
increase and another factor due to promotionof modernization. This positive increment inenergy demand seems unavoidable in the near
future, even if energy saving technologies canbe implemented to a moderate degree. For
example, the rate of energy consumption per
production unit in the heavy industries of developed countries might decrease, but this decrease will be completely compensated by the
rapid increase in energy demand in moderate
developed countries such as China, Malaysia
and Thailand. As can be seen in Fig. 4, energy consumption in East and South Asia area
is rapidly increasing with economic growth,and the percentage of imported fuels willreach almost 70% by the year 2010 [1].
Considering the two-sided nature of theenergy policy, that is, continuous growth ofmass consumption of the limited fossil fuels
on one hand, and the severity of the global
environmental issues on the other hand, theAgency of Industrial Science and Technology(AIST) of the Ministry of International Tradeand Industry (MITI) of Japan decided to establish the “New Sunshine Program” for the development of clean energy technology and environmental technology in 1993. Figure 5 illustrates the comprehensive structure of the
new program and its relation to the Sunshine
Project, which was formulated in May 1973prior to the first energy crisis and started in
1974. The Moonlight Project, which was initiated in 1978 and charged with the development of energy saving technologies, is anotherenvironmental technology project progressedfrom 1989 [5]. The past injected budgets arealso shown in the figure. While the new pro-

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1000
61

48
30

36

Energy Expenditure100

10100MB/day

200MB/day
15%

Percentages of Electrical
Energy in total
expenditure

1

9%World Population (Billion)

Energy Expenditure (MTOE/D)World Population

10

gram consists of three parts; a) Renewable
Energy Development Technology, b) High Efficiency Utilization of Fossil Fuels and Energy
Storage, and c) International Energy Cooperation, the so-called WENET (World Energy Network) for utilizing hydrogen fuel produced by
PV and a wide area energy distribution network system nicknamed “Eco-energy City”.

100

3. Key Issues for PV Industrialization

6%

0
1940

1950

1960

1970

1980

1990

2000

CALENDAR YEAR
Fig. 3 Growth of world population, and energy demand total energy and electricity demand. Percentages are theratios of electricity to total energy.

Energy Consumption
Domestic Production

80

8
69.2%
7
6

70

62.9%
55.4%

60

50.4%

5

50

4

40

3

30

2

20

1

10

Percentage of Imported Fuels (%)

Energy Consumption (Giga Barrels)

Percentage of Imported Fuels

0

0
1980

1992

2000

2010

Fiscal Year
Fig. 4 Transitions of energy consumptions and domestic productions in East and South Asia, and thepercentage of imported fossil fuels. (The area covers 11 countries)

32

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The direct conversion of solar radiation toelectricity by photovoltaics has a number ofsignificant advantages as an electricity generator. That is, solar photovoltaic conversion
systems tap an inexhaustible resource whichis free of charge and available anywhere in
the world. The amount of energy supplied by
the sun to the earth is more than five ordersof magnitude larger than the world electric
power consumption level that currently keeps
modern civilization going. Roofing tile photovoltaic generation, for example, saves excess
thermal heat and preserves the the local heatbalance. This means that a considerable reduction of thermal pollution in densely populated city areas can be attained.
Figure 6 shows the trend in solar cell module annual production in Japan since 1993 as
surveyed by the Optoelectronic Industry Technology and Development Association (OITDA)[6]. As can be seen from the figure, a remarkable increase of the annual production has
been seen since the start of the New Sunshine
Project in 1993. In spite of the various advantages of photovoltaic power generation as
mentioned above, a big barrier impeding the
expansion of large-scale power source application has been the high price of solar cell
module, which was more than $30/Wp (peakwatts) in 1974. That is, the cost of the electrical energy generated by solar cells was very
high compared with that generated by fossil
fuels and nuclear power generation. Therefore, the cost reduction of the solar cell is ofprime importance. To achieve this objective,
tremendous R&D progress efforts have been
made in a wide variety of technical fields overthe past 20 years, from solar cell materials,
device structure, and mass production processes to complete photovoltaic systems. The
result of the most recent fifteen years of R&D

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1992

1993

this project is its accelerated expansion. 73
sites generating 1.94 MW were installed in1998 alone. As the result of the accelerated
promotion strategy, the price for a 3-kW solar
photovoltaic system for a private home, forexample, has decreased sharply, down to 1/4
from 1993 to 2000 [4]. The figure also extrapolates the results to the expected cost of a massproduction scale program in the near future.

2020

New Sunshine projectB￥1550A) Renewable Energy
Development

1974

Sunshine Project
B￥440

Stop the Fossil Fuel Contamination
1978

Moonlight Project
B￥140B) High Efficiency Energy
Utilization & Storage

4.Future Prospects for Solar
Photovoltaics

Establish Eco-industrial Society
1989

Environmental
Technology
B￥15

The targeted milestone volume of 5 GWp
for PV installations by the year 2010 has been
the topic of many discussions. For example,
if 200 thousand solar PV homes were built
annually, which corresponds to nearly 10% of
the private homes built annually, the target
can be met in only five years assuming a 5 kW
PV/home. Figure 9 presents a scenario of cumulative PV system installations in Japan fromthe present day to 2030. The estimated installation volume of 65 GW in 2025 might
cover more than 40% of the peak savings ofelectrical energy even taking into account the
12.5% PV system operation efficiency.
Figure 10 shows results of a simulationon the future trend of primary energy consumption (a) and the electricity generated byC) World Energy Network(International Cooperation)
Keep Clean Natural Environment

Fig. 5 Organization and objectives of the New Sunshine Project

dized PV houses over the period of the recent
six years. As can been seen in the figure, thenumber of government subsidized PV househas been doubled each year. In the PV Field
Test Experiment, a total of 259 sites generating 6.84 MW have been installed during theseven years since 1992. A noticeable trend of140

Annual Production (MWp)efforts has been about a one order of magnitude price decrease, and currently, the module cost is less than $4/Wp in a firm bid for alarge scale purchase.
In December 1994, a new initiative in theJapanese domestic renewable energy strategy,
an initiatives of “Fundamental Principles toPromote New Energy Developments andUtilization” has been approved in a cabinet
meeting. Related actions in the form of tax
reductions, government subsidies, etc. wereapproved by the Congress on April 10, 1997[5]
. These strategies involve not only ministries
and government offices but also local government authorities and private enterprises.
The new government policy targets development and promotion of PV technologies
as being the most promised projects. Integrated installations of 400-MWp PV modules
by FY2000 and 5.0 GWp by FY2010 for Japanese domestic use have been scheduled, as
shown in Fig. 7. A special tax reduction forinvestment in renewable energy resources andgovernment financial support in the form ofa 50% subsidy on PV systems for public facilities, PV Field Test Experiments, and a 33.3%
subsidy on private solar houses, PV House
Planning of the field testing etc. are settled
and in progress as the goverment regulations.
Figure 8 shows number of government-subsi-

Progress of PV Module Production in JAPAN

128.6

120
100

88.8

Utility Power Use
Consumer Application

80
60
40

49.0

35.0
16.7

16.5

16.4

21.2

93

94

95

96

20
0

97

98

99

00

Calendar Year
Fig. 6 Recent transition of the PV solar module shipment in Japan

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33

Private Sectors, Enterprises

NEDO YEAR BOOK

5.0GW

tion of hydrogen energy in the Sahara desert
is planned using solar photovoltaics [9]. PhoPublic Building
Local Government etc.

400MW
Private House

About
35MW
2000

1995
Object Term
Generation Cost(￥/kWhr)2005

Near Term
25〜30

Present
30〜35

2010

Medium20〜25

Long Term
14〜20

Fig. 7 NSS project milestone for PV system installation up to 2010

various energy resources (b) [7]. As can beseen in the figure (a), about 50% of the primary energy could be supplied by non fossil
fuel which is nuclear plus renewable energy
including PV by about 2050. As for electric
power generation, 2040 will be the critical
period in which renewable energy sources
become the majority.
As described in the previous section, solar photovoltaic power generation is an almost
maintenance-free clean-energy technology.
Therefore, the penetration of PV technology

into utility power generation might be of prime
importance for market size expansion as awhole, using the scale merit of solar cells in
the PV system development . With an increasein feasibility of semi-power applications andthe exploitation of maintenance-free solar
photovoltaics, many methods of anti-pollution
processing can be performed with solar photovoltaic power. For example, ashing of pollutant gases by glow discharge decompositionand cleaning of water by electrochemical processing, as shown in Table 2 [8]. Mass produc-

25,741

17,421

8,229

tovoltaic water pumps and planting of trees
may also help to halt desert expansion and to“green” the desert. The “Gobi project” hasbeen organized for this purpose. In 1990, apreliminary study team began a survey of natural conditions in the Gobi Desert as part of aJapan-Mongolia program of cooperation [10].
These considerations indicate that an economically feasible age of photovoltaics will
come earlier than expected in the near future,if efforts continue to be made to promote R &D work and through market stimulation. The
most important emphasis should be placed on
stopping the effects of contamination by fossil fuels with a worldwide energy policy anddevelopment of this novel, clean-energy technology for the future benefit of all mankind.
The energy revolution from coal age tothe oil age was accomplished within only aquarter of a century from 1950 to 1975. The
reason why the transition was so short is thelarge scale merit of oil in terms of mass production at the petrochemical plant. With respect to scale merit, the merit of mass-produced solar cells might be greater than thatof oil at the stage of well-developed PV utilization systems. As has been reported elsewhere semiconductor devices have the highest scale merit, a fact that has been identified
as having been responsible for the solid-state
device revolution, from the age of the vacuum
tube to today’s electronics industry. For example, the DRAM (Dynamic Random Access
Memory) has a scale merit of 25%. Thismeans, if one increases production by one
order of magnitude, the cost per unit becomes
one fourth. Let us embark on a new energy
revolution with clean-energy photovoltaics.
Might it be possible to accomplish the cleanenergy revolution within the next 25 years? It
would be a worthy challenge, no longer simply a fanciful dream.

5,654

539

1,065

1994

95

1,986

96

97

98

99

2000

Fig. 8 Number of PV house approved for government subsidy

34

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PV system installation (GW)

10 4

10 3

A Scenario of
the Accumulated PV System
Installation in Japan

5. REFERENCES

500 GW[1]

150 GW

10 2

10 1

10

[2]

65 GW

[3]

30 GW

5 GW

NSS Project Milestone
Scenario 1
Scenario 2
Scenario 3
Extrapolated

0

[4]
[5]

36 GW

10

-1

2000

2005

2010

2015

2020

2025

2030

[6]
[7]

Calendar Year
Fig. 9 Scenarios of cumulative PV system installation in Japan[8]
Table 2 Contributions to the global environmental issues by PV

Local

[9]

(1) Solar PV power
generation

Clean sustainable energy
resource(2) Cleaning of polluted
airAshing of pollutant bases
by glow discharge
decomposition by PV[10]

Environment (3) Cleaning of waterElectrochemical processing
by PV(4) Generation ofhydrogen energy

Electrolysis of water by PV(5) Stop of desertification
Greening of deserts

PV water pumping at
plantations

GlobalY. Hamakawa, Oyobutsuri 69: 8, pp. 993-998(2000) and ibid 67:9, pp. 1023-1028 (1998).
US Solar Energy Industries Association (SEIA),
Directory of the US Photovoltaic Industry. 4,(1996).
Agency of Natural Resources and Energy, MITI,
Energy Flow Diagram of Japan in 1997, Energy Strategy of 21st century, July 15 (1998).
Y. Hamakawa: Proc. of 16th EC-PVSC, Glasgow,
PB1.2, May (2000)
K. Miyazawa, K. Katoh and K. Kawamura. Report of Solar Energy Division Meeting, Technology & Industrial Council, MITI, March 17(1997).
News Letter 6, OITDA, p.1, March 1 (2000)
K. Ito, Prospect of Fossil Fuels in the book of“Energy for 21st Century, 3rd annual Meeting
Report for Nuclear Fusion, June 12-13 (2000)
Y. Hamakawa, Proc. of WREC Regional meeting, Perth, Australia, p. 37, (1999).
K. Kurokawa, VLS-PV System, IEA-Task IV Report, May (1999).
News Paper Release, Nihon Keizai Shinbun,
May 11 (1990).

(b) Electric Power Supply and Its Prospect(a) Primary Energy Supply and Their Prospect
90

35
Renewable
Nuclear
Coal
Natural Gas
Oil

30
25

Renewable
Nuclear
Coal
Natural Gas
Oil

80
70

20

(PWH/Y)(GTOE/Y)

60

15

50
40
30

10
20
5
0

10

1980

2000

2020

2040

2060

2080

2100

0

1980

2000

Calendar Year

2020

2040

2060

2080

2100

Calendar Year

Fig. 10 Past expenses and prospects of the world primary energy demand (a) and that of electric power demand (b)for the 21st century calculated for the sustainable development scenario

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